Floating-type chill block



May l4, 1963 s. ELCHYSHYN 3,089,950

FLoATING-TYPE CHILL BLOCK FIG 2 INVENTOR. 'f -J- STEPHEN ELCHYSHYNATTORNEY May 14, 1963 s. ELCHYSHYN momma-TYPE CHILL BLOCK 3 Sheets-Sheet2 Filed June 23, 1961 NVENTR. STEPHEN ELCHYSHYN BYbd/ ATTORNEY May 14,1963 s. ELCHYSHYN 3,089,950

FLOATING-TYPE CHILL BLOCK Filed June 23, 1961 3 Sheets-Sheet 3 DVVENTUR.STEPHEN ELCHYSHYN ATTORNEY rates This invention relates to an improvedchill block, and more particularly pertains to a chill block adapted toconduct heat from rounded members in a welding operation.

Arc welding is commonly used for joining metals such as aluminum and itsalloys, magnesium and its alloys, copper, stainless steel and otherferrous and nonferrous alloys. It is particularly useful in sealing theends of thin-walled tubes with solid plugs. In this application, a highintegrity and helium leak-tight weld is generally mandatory. Also, it isdesirable that the weld bead be small and nearly flush with the tubesurface. This can only be achieved by uniformly cooling theheat-affected zone to protect the thin gauge tubing from the intenseheat of the welding arc. Such cooling is generally accomplished by meansof a chill block fastened contiguously to the periphery of the tubedirectly below the joint, to provide a path for the conduction of excessheat from the welding zone.

The conventional split-type, copper chill block assembly comprises abisected circular disc having a centrally located hole adapted toreceive a metal tube and fastening means for mounting the semi-circularportions of the disc around the surface of the tube. Such devices have anumber of drawbacks. For example, continuous contact between the sidesof the disc hole and the tube periphery is rarely obtained. This is dueto the xed size of the disc hole and the diameter tolerance ofcornmercial tubing which prevents a tight tit when the tube size iseither on the low or high side of nominal. Without continuous contact,the heat-affected zone bordering the joint is insufficiently cooled andan unreliable, low quality weld is produced. The discolored heat bandwhich normally occurs below a welded joint is affirmative evidence ofthe inadequate cooling elfect of a conventional chill block. The heatband is very narrow at points of good contact but becomes much wider inthe area of no contact.

There are numerous adverse effects resulting from inadequate cooling inthe heat-affected zone. The usual mechanical effects of welding, such asdistortion and residual stresses, are aggravated. High residual stressesmay reduce the strength of the welded joint or even cause crackingduring welding. Nonuniform cooling may also cause weld porosity and alarge, irregular weld bead. ln addition, metallurgical transformationsin the metal may be of Such magnitude as to change its properties. Forexample, over-heating causes excessive grain growth which producesbrittleness. In type 304 stainless steel, excessive grain growthproduces the phenomenon of intergranular attack. The carbon in steelcombines with the chromium to form chromium carbide which migrates tothe grain boundaries, severely decreasing the strength of the steel andrendering it susceptible to corrosion. The ultimate result of inadequatecooling in the heataffected zone is, therefore, a low quality weld,unacceptable for most industrial applications.

Accordingly, an object of this invention is to provide an improved chillblock.

fllt

ice

Another object of this invention is to provide a iloating-type chillblock wherein continuous contact and uniform pressure between aworkpiece and the block is maintained irrespective of changes in thediameter or configuration of the workpiece.

Another object is to provide a chill block which accommodates membershaving various diameters.

Another object is to provide a chill block having means forautomatically adjusting its position in response to variations in thediameter or configuration of the workpiece, thereby avoiding loss ofcontact.

A further object is to provide a chill block which conducts heat fromthe heat-affected area with such effectivness that a high integrity,helium-leak-tight weld is produced.

A still further object is to provide apparatus for arc welding roundedmembers.

These and other objects and advantages of the present invention will bemore apparent from the following detailed description and drawings,hereby made a part hereof, in which:

FIG. 1 is a partially sectioned plan view of the present invention.

FIG. 2 is a fragmentary plan view in section of an alternate arrangementof a portion of the embodiment of FIG. l.

FIG. 3 is partially sectioned elevational view of the chill block inassembled relationship with its associated components during a weldingoperation.

FIG. 4 is a perspective view showing the chill block in the samerelationship as in FIG. 3.

The preferred embodiment of my chill block will be described inconnection with arc welding end plugs in thin-walled tubing. In FIG. l,chill block 10 is discshaped and composed of a metal having a highthermal conductivity, such as copper. It includes a plurality ofsemi-circular recesses 12 defined by surfaces 14 which receive andpartially encircle a tube 16 (FIG. 4) being welded. Contact with tube 16is made along surfaces "14. The recesses 12 are equally spaced aroundthe peripheral surface 18 of chill block 10 and each recess has adifferent radius of curvature so that various size tubing can beaccommodated by the chill block. The radii of curvature of the recessesare determined on the basis of providing more than but less than 180 arcof contact between surface 14 of recess 12 and the surface of tube 16.This is accomplished by making the recess radius slightly larger thanthe tube radius.

Two important objectives of my invention are accomplished by suchcurvature radii. First, continuous contact between tube 16 and chillblock 10 can be maintained if the arc of contact is less thannotwithstanding variations in tube diameter due to the commercialtolerance factor or changes in tube configuration as a result ofdistortion during welding. Also, although only partial contact is madebetween tube 16 and chill block 10, effective cooling is still obtainedwhen the arc of contact covers at least 90 of the tube surface.

The manner in which Contact between the chill block and the tube ismaintained during welding will now be described. Turning to FIGS. 3 and4, a spring 2.0' mounted on the shank 22 of handle 24 exerts a lateralpressure which holds chill block 10 in firm contact against tube 16during the welding operation. Spring 20 is compressed between surface 14of chill block l0 and a shoulder 26, defined by shank 22 and body 28 ofhandle Z4. Each recess 12 has a radially `directed blind hole 30 intowhich shank 22 is inserted in loose-fitting relationship. Alternatively,the diameter of hole 30 could be made large enough to accommodate bothyshank 22 and spring 20, as shown in FIG. 2. In the FIG. 2 arrangement,the spring would abut against the bottom 32 of hole 30. Handle 2d isplaced in the blind hole located diametrically from the recesscontaining the tube being welded. In this manner, the lateral forceexerted by spring 20 is applied normally to the surface of tube i6. Theshank end 34- of handle 24 is spaced from the bottom 312 of hole 30 topermit free lateral movement of chill block i against spring 20. Thus,the chill block has a floating action which ensures continued contactand uniform pressure between the tube and block. This iioating actionavoids loss of contact if the tube `diameter is on the low side of itsnominal size or in the event of tube distortion. Also, if tube 16expands from the welding heat, block l0 is free to .move laterally inthe direction of the expansion and thereby maintain approximatelyuniform pressure against tube I6. In its operative position, the bodyend 36 of handle 24 abuts against the welding chamber 38 at 40 forsupport. If a welding chamber is not being used, a bracket or othersuitable means could be employed to provide support for handle 24.

Preliminary to welding, tube 16 is located in an apv propriate recess112 and handle 24 is inserted in a hole 30 diametrically opposite thetube with its body end 36 contacting welding chamber 38 at 40. In thisposition, spring 20 is compressed between a recess surface 14 in chillblock and shoulder 26 on handle 24. The lateral `force exerted by thespring maintains the chill block in contact with tube 16 and -supportshandle 24 in the horizontal position shown.

As seen in FIGS. 3 and 4, during a welding operation, tube i6 is fixedto the turntable 42` by a clamp (not shown), and a conventional driveunit (not shown) rotates the turntable and tube together. The electrode44 is positioned in proximity to the joint 46, and the chill block isheld directly beneath the electrode in sliding contact with the tube.Current is -supplied through the electrode holder 4S to the electrode44, thereby producing an electric arc `between tube i6 and electrode tip50. The intense heat of the arc unites the metals by fusion. Heat isdrawn away from the workpiece by conduction through block 10, and thencetransferred by radiation to the environment; mechanical cooling of theblock is not ordinarily required.

It can be seen that the floating feature of my chill block together withits recesses for receiving tubes to be welded overcome the disadvantagesof the conventional chill block mentioned above. By maintainingcontinuous contact and uniform pressure between the chill block andtube, the zone of the tube directly below electrode tip S0 is moreeffectively cooled. This minimizes tube distortion with its resultingresidual stresses and produces a high quality weld having superiorstrength and metallurgical structure.

It is to be understood that the above-described preferred embodiment isonly -by way of illustration and not for purposes of limitation. Thescope of the invention is understood to be limited only as set forth inthe following claims.

What is claimed is:

1. Chill block means for conducting heat from a member subjected to aheat source, comprising a movable, unitary block having at least onesurface defining a recess therein for receiving said member, said recessbeing adapted to contact from about 90 to about 180 of the surface ofsaid member, and means for urging said block against said member,thereby maintaining contact between said recess and said member.

Z. A chill block adapted to conduct heat from a work member exposed to aheat source, comprising a movable, unitary block having a plurality ofsurfaces defining recesses therein, each of said recesses having adifferent radius of curvature for accommodating work members havingvarious radii, the radius of curvature of each recess being larger thanits related work member to provide an area of contact between -saidblock and said member from about to about 180 of the surface of saidmember, and means for urging said block against said worker member,thereby maintaining contact between said recess and said work member.

3. A chill block adapted to conduct heat from a rounded workpiecesubjected to a heat source, comprising a movable, unitary block having acircumferential surface dening at least one concave recess the-rein forcontacting said workpiece, said recess circumscribing from about 90 toabout 180 of the surface of said workpiece, and means for urging saidblock against said workpiece, thereby maintaining said recess in contactwith said member, said means being located on an opposite side of saidblock to said workpiece.

4. A chill block comprising a block having a circu-mferential lsurfacedefining a plurality of equally spaced, semicircular recesses ofdifferent radii for receiving workpieces exposed to a heat source, saidrecesses adapted to contact from about 90 to about 180 of the surface ofsaid workpiece; and means Afor maintaining said block in contact withsaid workpiece, said means being located on an opposite side of saidblock to said workpiece, and including spring means for maintaining saidblock against said workpiece.

5. A heat conducting chill block composed of a high thermal conductivitymaterial which cools the heat-affected zone of a rounded workpiece beingwelded, comprising a block having a circumferential surface, saidsurface deiining a plurality of equally spaced recessed surfaces adaptedto circumscribe and contact from about 90 to of the surface of a roundedworkpiece, said recessed surfaces having different radii of curvaturewhereby said block is adaptable to workpieces of Various diameters; andspring loading means for maintaining contact between said workpiece andsaid block comprising a handle engageable in said block, said handlehaving a shoulder portion and a spring mounted on said handle, saidspring being compressed between said shoulder and said block and urgingsaid block against said workpiece.

6. The chill block of claim 5, wherein `said recessed surfaces of saidblock define internal radial bores adapted to receive said handle.

7. The chill block of claim 5, wherein said handle is operativelypositioned in a. bore opposite the recess containing said workpiece,whereby the force exerted by said spring is applied normally to saidworkpiece.

8. A chill block for conducting heat from the heataected zone during thewelding of rounded workpieces, comprising a block having a plurality ofsemi-circular recessed surfaces which receive said workpieces andwherein said chill block contacts from about 90 to about 180 of thesurface of said workpiece, said recesses having different radii ofcurvature whereby said chill block is adaptable to rounded workpieces ofvarious diameters, each of said recesses containing a bore extendingradially inward in said block, means `for spring-loading said blockagainst said member comprising a handle positioned in, and spaced fromthe end of, a bore opposite the recess containing said workpiece, andhandle having a shank portion and a body portion defining a shouldertherebetween, a spring mounted on said shank between its associatedrecess and said shoulder, whereby the spring action provided maintainscontact between said block and workpiece.

9. Arc welding apparatus adapted to fusion weld rounded members, saidapparatus comprising an electrode, means for electrically ener-gizingsaid electrode, means for supportably rotating said members, a chillblock comprising a block having a circumferential surface defining aplurality of semicircular recessed surfaces which receive said memberand wherein said chill block slidingly contacts from about 90 -to about180i" of the sur-face of said member adjacent `said heat-aiected zone,said recessed surfaces having diierent radii of curvature whereby saidchill block is adaptable to rounded members of various diameters, andmeans for maintaining contact between said member and said block,whereby :said chill block is repositionable in response to changes inthe configuration of said member and continuous contact is therebymaintained.

References Cited in the le of this patent UNITED STATES PATENTS

1. CHILL BLOCK MEANS FOR CONDUCTING HEAT FROM A MEMBER SUBJECTED TO AHEAT SOURCE, COMPRISING A MOVABLE, UNITARY BLOCK HAVING AT LEAST ONESURFACE DEFINING A RECESS THEREIN FOR RECEIVING SAID MEMBER, SAID RECESSBEING ADAPTED TO CONTACT FROM ABOUT 90* TO ABOUT 180* OF THE SURFACE OFSAID MEMBER, AND MEANS FOR URGING SAID BLOCK AGAINST SAID MEMBER,THEREBY MAINTAINING CONTACT BETWEEN SAID RECESS AND SAID MEMBER.